LED’s themselves come in various shapes and sizes. The most common LEDs used on boards for linear lighting are 3x2mm or 3x3mm.

LEDs are produced on wafers up to 300 millimetres in diameter, so thousands can be produced at a time. The manufacturing process for the wafer involves many steps – initially the manufacturer must ensure that the silicon is as pure as possible. Any slight variation across the wafer can mean that some LED’s can perform differently to other LEDs from the same wafer.

Once the LEDs are cut from the wafer, they are packaged into the white plastic housing that surrounds them. Again, very slight differences in how the LEDs are processed at this stage can affect how the LED performs once finished. After manufacturing is complete, all LEDs are tested based on the following criteria:

  • Forward voltage
  • Colour temperature
  • Output

LEDs of a similar value are batched (binned) together. This ensures that when purchasing a batch of LEDs, all of the components supplied have characteristics within a known, and acceptable, tolerance.

Forward voltage

Forward voltage is the voltage required to “switch on” the LED and allow current to flow through it. It is important that the forward voltage is known so that the luminaire manufacturer can specify the correct driver for the light fitting.


The output of the LEDs needs to be known, so that a luminaire is not manufactured with one part of it brighter than another part. Consistency between luminaires is essential also.

Colour temperature

Colour temperature is the is the colour of the light itself. This is an involved topic and so it will have its own section. Essentially light can appear warm (orange – think sunrise & sunset) or cool (think bluey white – like the middle of a sunny summers day). LEDs need to be supplied with consistent colour, otherwise the end result is not very inviting.

Those are the features that are used to group LEDs together. The process is known as “binning”. I hope you have found this helpful. For any questions or comments, feel free to contact us.